Process aitd machine eob die casting



April 9, 1929. J CROWLEY HJQSMU.

4 PROCESS AND MACHINE FOR DIE CASTING Filed Feb. 9, 1927 5 Sheets-Sheet A R-in 9, 1929. J, R CROWLEY nmsmn PROCESS AND MACHINE FOR DIE CASTING Filed Feb. 9, 1927 3 Sheets-Sheet 2 K Hz] [5 Apkill 9, 1929. CROWLEY Lwagfill PROCESS AND MACHINE FOR DIE CASTING Fi led Feb. 9, 1927 3 Sheets-Sheet Patented Apr. 9, i929.

JOSEPH P. CROWLEY, OF TOLEDO, OHIO.

PROCESS AND MACHINE FOR DIE CASTING.

Application filed February 9, 1927.

My invent-ion has for its object to provide a process and a machine whereby metals or alloys of metals may be rapidly cast to form 1n ametal mold. The invention particularly provides for maintaining the sprue or orifice oi the mold at a temperature which 1s, approximately, that ot' the molten metal and to a pressure that is substantially constant and slightly greater than atmospheric tor mamtaining a very slow movement through the opening or sprue of the mold, and for subjecting the interior of the mold, when closed, to pressure that is below atmospheric in order to rapidly fill the mold; the orifice of the mold being maintained at a high temperature, the metal of the mold will readily separate from that of the sprue.

The steps of the process may be varied without departing from the spirit of the invention and, moreover, machines containing the invention in which the process may be conducted, may partake of ditl'erent forms and still embody the invention. To illustrate a practical application of the invention, 1 have selected a machine and a process as an example of structures and processes involving the use of the invention, and shall describe them hereinafter. The machine selected, for purposes of illustration, is shown in the accompanying drawings.

Fig. 1 illustrates apparatus in which the machine involving the use of my invention is employed and wherein the process may be conducted. i i 2 is a view of a section taken on the plane of the broken line 2-2 indicated in 1. Fig. 3 is a view of a vertical section of the machine taken on the plane of the line indicated in F 2. Fig. 1 is a broken view showing parts oi the machine and also illustrates a section taken on the plane of? the line ll indicated in Fig. 2. Fig. 5 illus trates a part of the machine shown in Fig. t from the side opposite to that shown in Fig. 4. F 6 is a view or"? a section taken on th plane of the line 66 indicated in Fig. 3. Fig. 7 is an inve "ted view oi the mold. Fig. 8 is a view of a section taken on the plane of the line 88 indicated in Fig. Fig. 9 is a View of a section taken on the alane of the line 9-9 indicated in Fig. 4. 1O illustrates an air blower pipe and means "for controlling the flow of air therethrough.

In the particular apparatus shown in tl.e drawings, a reservoir of the heated metal to be cast is maintained above the mold so as to keep the mold substantially at a suitable Serial No. 166,851.

working temperature. Preferably, the upper part of the mold constitutes the bottom of the reservoir. The reservoir may be made in any form and its temperature may be sustained by maintaining a substantially constant or intermittent flow of metal into the reservoir. If desired, means may be provided for heating and thus maintaining the temperature of the reservoir and the metal that is contained therein. Thus the reservoir 1 is closed at its bottom by the top of the mold 2, except for the inlet or inlets 3 into the matrix of the mold which is made very small in order that when the mold is open there will be merely a dripping of the metal on the mold which, however, may be readily collected and remelted, means, however, being provided for causing a rapid movement of the metal into the mold when the mold is closed. Thus the moldinlet or sprue will be maintained at a high temperature and will prevent freezing or congealing of the metal in the opening that leads to the matrix of the mold. 'lhe outlet ot the reservoir of molten metal being through the bottom into the mold prevents clogging by reason of dirtor scum that always floats on the surface 01" the molten metal. The upper half 01? the mold being hot permits a rapid break between the metal in the matrix and the metal of the sprue holes 3. Also the metal of the matrix being in direct communication with the metal of the reservoir, prevents shri rage or piping. The openings 3 are made very minute and, consequently, in order to maintain at leasta slight movement of the metal through the openings, they are subjected to the hydrostatic pressure due to the weight of the metal in the reservoir 1, so that when the mold 2 is closed, the metal may be forced into the mold since it will have free passage into the mold as the openings are not obstructed by any solidified or congealed metal or foreign material. Molten metal may be caused to flow continuously into the reservoir 1 or the metal maybe caused to flow intermittently and at times that are regulated according to the movement of the metal through the openings or sprues of the mold. In the apparatus shown in Fig. 1 a melting pot or furnace 5 is conventionally shown wherein metal may be heated by means of any suitable heating means, such as, the blow pipe 6. The

pot may be tilted or have an outlet or spout 7 so that as the metal, that is placed therein, is melted it will flow beneath the bridge 8 that extends across the spout 7 and the metal will do into a pipe or trough 9 from the spout. The metal is directed throi'egh the trough 9 into the reservoir 1. This will cause a substantially constant movement of the metal from the melting pot 5 into the reservoir 1, which will be substantially according to the rapidity at which the n'ietal melts in the pot 5. ln order to maintain the level of the re: rvoir 1 substantially constant, which is normally desired owing to the fact that it depends upon the temperature of the metal in th reservoir and also the pressure, the metal to be melted placed in the pot 5 in quantities that the blow pipe 6 will melt so as to maintain a flow in the reservoir about equal to the how of the metal from the reservoir 1 through the openings or sprues 3 into the mold 2.

in order to maintain the metal in the reservoir 1 at a desired temperature and thus to maintain the top of the mold 2 at the desired temperature, to permit at least some move ment through the sprues of the mold at all times, the reservoir may be heated. If desired, the exterior of the reservoir may be surrounded by a suitable shell or wall which may be formed of heatinsulating material and the blow pipe 16 may extend into the shell 15 for the purpose of heating the reser- Voir 1. The temperature that is produced within the shell 15 may be regulated by suitable valves 17 and 18 that are located in the pipes that lead to the blow pipe 16.

The mold 2, as is common in the making of castings, is formed of two parts 20 and 21, the upper part 21 having one or more openings 8. The openings 3 are, preferably, oblong in form and the opposing surfaces of the openings are about 0.018 of an inch apart and so that the metal cannot freely flow therethrough by gravity. The openings 3 may be made of any desired length, preferably, however, not to exceed an inch or so, depending on the contour of the upper surface of e matrix of the mold. The upper part of the mold 21 is also provided with an indentation 22 which forms a funnel for directing the metal to the openings 3. Preferably, the in dentation 22 is sufiiciently deep to form a very thin section of metal in the upper part 21 of the mold where the openings 3 are located, and so that the tiickness of the metal, where the openings 3 are located, is, preferably, not more than 3/16 of an inch thick. These dimensions, however, may be varied with the understanding that the size of the openings 3 is such as to prevent a free movement of the metal through the openings by gravity alone and no more than mere dripping of the metal when subjected to the hydrostatic ressure due to the depth of the metal in the reservoir 1.

The matrix of the mold, of course, may conform to any desired shape accordin to the form of the casting-s that are to be made. Means may be provided for opening and closing the mold by movement of the lower part 20. In the form of construction shown the lower part 20 is hingedly connected by the pintle 23 to the upper part 21 of the mold and a push rod 2 is pivotally connected to the lower part 20 of the mold by means of a suitable pin 25, whereby the lower part may be dropped so as to swing on the pintle 23 and open the mold, or the part 20 may be moved upwards against the part 21 so as to close the mold. The push rod 24 may be operated by any suitable means to cause the swinging movements of the lower part 20 of the mold, that is, to a ternately open and close the mold.

In the form of construction shown, the push rod 2 1 is supported by i'neans of a crank 26 and is operated by a cam 27. The crank 26 is supported in standards 28 that support the shell 15 and the cam 27 is keyed to a shaft 29 which is also rotatably supported in the standards 28, suitable bearings being provided for the crank 26 and the shaft 29.- The cam 2'? is operated by suitable motor 30 that drives a worm. 31 which meshes with the worm Wheel 32 to cause rotation of the shaft 29 and, consequently, rotation of the cam 27. The cam 27 is provided with a raised portion 33 that is concentric with the shaft 29 which operates on a roller 34 rotatably located on the crank 26 and at the end of the push rod 24 to close the lower part 20 of the mold 2, and maintain it closed for a desired period of time which will be according to the speed of the motor and the length of the arc of the concentric raised portion of the cam 27. This period is sufficient to permit the matrix of the mold to be filled with the molten metal from the reservoir 1. At the IiUll'tlillOll of each of the mold filling periods, the concentric raised portion 33 of the cam passes from between the roller 3 1 and the shaft 29 which allows the lower part 20 to drop away from the upper iart and so as to dump or drop the casting formed within the mold.

Since the size of the openings 3 is such to prevent free movement of the molten metal therethrough,except possibly a small drip due to the pressure of the molten liquid at the bottom of the reservoir 1, m ins is provided for greatly increasing the difference in pressure above and below the thin section of the metal of the mold in which the orifices 3 are located. This is done by withdrawing air from within the matrix of the mold by means of an air pump 10 which is connected to a closed cylinder 41, from which air is drawn by the pump to maintain the substantially constant low pressure therein. The cylinder 1-1 is connected to the upper part 21 of the mold by 11 cans of the pipes 42 and 43. This connection. is controlled by means of a valve 14 located in the pipe 12. The pipe 13 is connected to passage-way 5 formed in the upper part 21 of the mold. A part of the passage-way is circular and surrounds the edge of the matrix of the mold at the point of juncture of the upper and lower surfaces thereof. Thus the passage-way 45 may be closed on one side by the lower part 20 of the mold. The passageway 45 communicates with the matrix through very minute openings 46 that may be formed by very shallow indentations located at the edge of the portion of the matrix formed in the upper part 21 of the mold. When, therefore, the mold is closed, air will be drawn from the matrix of the mold through the very thin space or spaces located at the plane of contact between the upper and lower faces of the upper and lower parts of the mold respectively. This will increase the difference in pressure at the upper and lower faces of the thin section 48 which will cause the metal to flow from the reservoir 1 into the matrix of the mold, the orifices having been kept free from congealed metal by the temperature of the metal in the reservoir, which is located in contact with the upper partof the mold.

The valve 44, which may be of any suitable type, is controlled by means of a cam 49 which is also located on the shaft 29. In the form of construction shown, the movable valve member 50 may be operated by means of the spring 51 which presses against the valve casing and against the bell crank lever 52 when it is released by the operation of the cam 49. The cam 49 has a raised portion 53 which operates on the bell crank lever 52 to close the valve 44. The raised portion 53 is substantially concentric with the shaft 29 and it also has a portion 54 that allows the bell crank lever 52 to be operated by the spring 51. The portion 54 has an edge that is substantially concentric to the shaft 29 and, measured in degrees, is substantially the same in length as that of the raised portion 33 of the cam 27 whereby the valve member 44 will remain opened by the operation of the cam 49 while the mold is kept closed by the operation of the cam 27, and the valve 44 will be kept closed the remainder of the time. This will draw the metal through the orifices 3 and permit the mold to be completely filled. Ordinarily, the vacuous condition that is produced in the mold will cause the metal to freely flow and fill the mold, although the top of the matrix of the mold is located slightly above the openings 57 through which the air is drawn to produce low pressure within the mold. However, if it is desired, one or more passage-ways 57 may be connected with the top or the matrix of the mold and with the passage-way 45 so as to draw the air from the top of the matrix of the mold.

Also, if it is desired to slightly chill the lower edge surfaces of the upper part of the mold that forms the upper surface of the matrix, particularly at the lower ends of the orifices 3, it may be done by directing a stream of water through the passage-way 60' which is connected to the water pipe 61 that may be controlled by suitable valve 63, or it may be done by an air blower 64 that is located at the edge of the lower part 20 of the mold and so that the instant the mold is open the air blower will blow air against the lower edges of the orifices 3.

The air blower 64 is located at the end of the air pipe 65 which is controlled by the valve 66 similar in form to the valve 63. The valves 66 and 63 may be operated by the rod 67 which is connected to an arm 68 located on the bell crank lever 52. The valves 63 and 66 are each provided with arms 70 and 71 that will be operated when the link 67 is operated by the bell crank lever 52. The arm 68 will, therefore, be actuated by the cam 53 to open the valves 63 and 66 when the bell crank lever is operated to close the valve 50. The bell crank lever 52 is provided with a roller 69 which is moved by the cam 49 to close the valve 50 and to open the valves 63 and 66 and, subsequently, close the valves 63 and 66 and open the valve 50. Thus the air or water, or both, is turned on when the suction on the metal ceases, provided it is found desirable under certain operative conditions, and when castings of certain metals or alloys of metals are made.

In the operation of the apparatus the metal is melted in the pot 5 until it may be poured into the trough 9 or until it overflows into the trough 9. The metal is melted, preferably, according to the rate that it is drawn from the reservoir 1 into which it is directed by the trough 9. If the heat of the metal in the reservoir 1 is not sufficient to maintain the outlets 3 clear of congealed metal, the upper portion of the mold and the reservoir may be heated by a flame from the blow pipe 16. On the other hand, if the alloy is of such a character that it will rapidly pass through the openings 3, notwithstanding the very minute size of the openings, the rate of flow or drip of the metal, when the mold is open, may be reduced as may be desired by slight chilling action which, however, is not so great as to cause chilling or freezing of the metal within the'orifices by allowing the water to flow through the pipes 63, or air to flow into the pipe 65 to the blower 64. The flow of these fluids, however, will be timed by means of the cam 49 Operating through the valves 44, 63 and 66 and will also be timed with respect to the opening and closing of the mold by the cam 27 which is located on the same shaftthat the cam 49 is located on, whereby the metal will be drawn through the very narrow orifices 3 by the differences in pressure produced on opposite faces of the thin section 48, in which the orifices are located, by the low pressure which is maintained by the pump 40 in the cylinder 41, and which will be disconnected from the mold when the ALL mold is opened, While at the same time, if it is found desirable, the chilling action of the blower 6st or oil the water through the passage-way 60, or both, may be brought about by opening of the valves 63 and 66 through the movement of the rod 67 produced by the bell crank lever 52 and the cam 49.

I claim:

1. in a machine for casting metals, a mold having upper and lower parts, a reservoir for containing molten metal and located contiguous to the upper part oi the mold for maintaining the liquid metal in contact with the said part of the mold at all. times and the said part at a tmnperature substantially equal to that of the metal between castings, the said upper part having an orifice for permitting the metal to enter the matrix oi? the mold, means for moving the lower part of the mold to open and close the mold for discharging the castings.

2. in a machine for casting metals, a mold having upper and lower parts, a reservoir for containing molten metal and located contigir ous to the upper part of the mold for 1 raintaining the liquid metal in contact with the said part and at a temperature substantially equal to that of the metal at all times, the said upper part having an orifice for permitting the metal to enter the matrix of the mold, the said parts of the mold hingedly connected together at one side of the said parts, and means for swinging the lower part about the hinged connection to open and close the mold for dumping the castings.

3. The process of producing metal castings in a mold i'rom molten metal SU'illClQntin quantity to produce a plurality of castings which consists in maintaining the said molten metal in contact with the surface of the inlet of the mold at all times during and between each succeeding casting to maintain the temperature 01E the portion of the mold about the inlet at a temperature substantially equal to that of the molten metal to prevent congealing oi? the metal in the said inlet, and subjecting the molten metal at the inlet to a difference of pressure that is greater when the mold is Closed than When the mold is open to cause the metal to flow slowly when the mold is open and to flow faster for quickly filling the mold when the mold is closed.

a The process of producing metal castin a mold, which consists in maintaining molten metal in contact with the surface of the inlet of the mold at all times and at a material amount of substantially constant hydrostatic pressure when the mold is open to maintain a slow movement of molten metal through the inlet to maintain the temperature of the. surface of the inlet substantially the same as that oi the molten metal at all times.

5. The process producing metal castings in a mold, which consists in maintaining molten metal in contact with the surface of the inlet of the mold at all times and at a material amount oi substantially constant hydrostatic pressure when the mold is open to maintain a slow movement of molten metal through the inlet to maintain the temperature of the surface oi the inlet substantially the same as that o1 the molten metal at all times and subjecting the metal at the inlet to an increased pressure di'ti erence when the mold is closed, to cause the metal to quickly fill the mold.

6. In a machine for casting metals, a mold having two parts, a reservoir for containing molten metal and located in contact with one of the parts of the mold, an orifice interconnecting the said reservoir and the matrix of the mold and extending through the said part and located at all times below the level of the molten metal in the reservoir, and means for varying the pressure of the metal in the reservoir at the orifice for causing the molten metal to move through the o-rii'ice into the mold when the mold is closed.

in witness whereof I have hereunto signed my name to this SjlGClllQfitlOll.

JOSEPH P. CROWLEY. 

